Quiz #27 Answer: EKG with ST segment elevation

6 yr old boy, s/p Repair of subaortic membrane. Two EKGs with time are given – both recorded on the day of surgery. One is immediately after coming from OR and the other ~10 hrs later. Second EKG was performed due to EKG change in monitor. Hemodynamically stable. Patient is sleeping without any complaints.

1)      Describe the most significant change.

2)      What is the possible reason for the change?

Answers:

1)      St elevation in every lead except aVL and V1.

2)      Possible pericarditis – post-op.

Other possibilities:

1) Acute Myocardial Infarction

2) Hyperkalemia

3) Hypothermia

(All are discussed below in detail).

Patient Follow-up: No further investigations were done. Discharged home in 48 hrs. without any problems. Treated with Ibuprofen just like many other postop. cardiac patients. Followed by outside cardiologist.

Pericarditis: Characteristics of changes in Pericarditis: ST segment with concavity upwards and presence of this change in multiple leads favors diagnosis of pericarditis.

Ischemia or infarction changes will occur in specific areas that are affected (i.e. inferior leads, anterior leads, lateral leads, etc.) with reciprocal changes in “opposite” leads. Pericarditis typically involves ST elevation “all” leads and may not follow specific lead groups.

(Principles of Clinical Electrocardiography (11^th ed) by Mervin J. Goldman. Lange Medical Publications 1982, page 285).

AMI: Figure below shows acute EKG changes in inferior wall infarction in column B (Column A is normal EKG for comparison. Note the shape of ST segment (covexity upwards in II, III & aVF) and reciprocal changes in I, aVL, V1-V6).

(From Principles of Clinical Electrocardiography (11^th ed) by Mervin J. Goldman. Lange Medical Publications 1982, page 170)

Hyperkalemia: Hyperkalemia can present this way, but usually is associated with Tall peak T waves as well. Patient’s K in ABGs were normal. Below is an EKG strip from a newborn with Sr. K 9.1. The ST elevation and Tall T waves in hyperkalemia resemble AMI changes. But, these changes (at this Sr. K levels) will be interspersed with other EKG changes of QRS complex and arrhythmias as in this patient. (This baby was diagnosed with congenital adrenal hyperplasia later. Cardiology was consulted for bradycardia!)

Hypothermia: Occurs with characteristic appearance of Osborne waves (arrows). And, also occur with prolongation of QRS duration and QTc. Therefore, it is reasonable to do a 12-l2-lead EKG before instituting hypothermia protocol as an elective procedure (not possible when initiated during CPR).

(Image from internet)